With the development of the semiconductor industry, integrated circuits with higher performance and more powerful functions require greater element density. Thus, the sizes of the components need to be scaled further. Accordingly, in order to improve the performance of the Metal Oxide Semiconductor Field Effect Transistor (MOSFET), the gate length of the MOSFET should be further reduced. However, with the continuous reduction of the gate length, when the gate length is reduced to approach the width of the depletion layer of the source and the drain, for example less than 40 nm, severe short channel effects (SCE) occur, which disadvantageously leads to deterioration of device performance and difficulty for large scale production of integrated circuit. It has become a challenge in large scale production of integrated circuits to reduce and effectively control the short channel effects. It is described in pages 1-19 of the Article written by Thompson S et al.: “MOS Scaling: Transistor Challenges for the 21st Century”, Intel Technology Journal Q3'98, that Halo ion implantation and retrograded well can alleviate short channel effects. In the prior art, the dopants are often improperly introduced into the main parts of the source region and the drain region by the Halo ion implantation to be overlapped with the doping in the source/drain regions, causing increase in the band-band leakage current and source and drain junction capacitance in the MOSFET devices, thus results in deterioration of device performance.
Therefore, in order to improve the manufacture of high-performance semiconductor devices, there is a need for a semiconductor device and method for manufacturing the same to reduce improper doping to the source and drain regions during formation of a Halo ion implantation.